The present invention relates to distillation systems primarily directed to recovery of industrial oils, and the like. More specifically, the invention relates to improvements in distillation systems wherein liquids used in an industrial process are passed through a heater, a still and condenser to recover the more volatile components for re-use in the process.
In manufacturing processes, such as metal rolling mills, a cooling and lubricating liquid is continuously flushed across the surface of the workpiece. Liquids commonly used for such purposes include mixtures of various petroleum distillates in desired proportions suited to the particular process. The liquid becomes contaminated during use with dirt and other solids, as well as other liquids or semi-liquids such as lubricating oils and greases used for operating parts of the process machinery. Although solid contaminants are normally removed by filtration, distillation systems are employed to separate the more volatile process liquids from the heavier oils, etc. with which they become mixed.
Conventional distillation systems include a still which receives heated, contaminated liquid from a suitable heat exchanger. The enclosed chamber of the still is maintained at a sub-atmospheric pressure at which the more volatile components of the heated liquid will vaporize, leaving the other components in liquid form within the still, from which they may be discharged to a holding tank or returned to the heater, such liquids being commonly known as "bottoms". Vaporized liquid from the still is passed to a condenser, where it is cooled to return to the liquid state and may then be returned to the process wherein it is used.
It is, of course, desirable to conduct the distillation process at optimum efficiency in terms of volume of recovered process liquid in relation to energy used. The principal object of the present invention is to provide a distillation system of the type outlined above which operates at improved efficiency in relation to prior art systems.
Another object is to provide an industrial oil recovery distillation system wherein process liquids are heated prior to introduction into the still in a manner which enhances system efficiency.
A further object is to provide novel and improved apparatus for effecting vaporization of volatile components of industrial process liquids within a still.
An additional object is to provide a preheater tube assembly which may be easily and economically incorporated in a heater for an industrial oil recovery distillation system.
Yet another object is to provide novel and improved apparatus for effecting vaporization of volatile components of liquid within the still of an industrial oil recovery distillation system.
A still further object is to provide a novel and improved method of operation of a distillation system for recovery of industrial process liquids which enhances efficiency and reliability of operation.
Other objects will in part be obvious and will in part appear hereinafter.